Vulnerability discovery in encrypted closed source PHP applications

Security audits of PHP applications are usually performed on a source code basis. However sometimes vendors protect their source code by encrypting their applications with runtime (bytecode-)encryptors. When these tools are used source code analysis is no longer possible and because these tools change how PHP works internally, several greybox security scanning/fuzzing techniques relying on hooks fail, too.

This talk will show how different PHP (bytecode-)encryptions work, how the original bytecode can be recovered, how vulnerability discovery can still be performed with only the bytecode available and how feasible PHP bytecode decompilation is.